This invention generally relates to cooking/food processing apparatuses. More specifically, this invention relates to automatic frying apparatuses for both deep and shallow frying.
Fried foods, such as fried shrimp, fried fish, fried chicken, etc., are tasteful. Two of the most important characteristics of fried foods are: outside, golden and crispy; and inside, juicy and tender. There are some issues associated with preparing fried foods at home.
First, the contact of moisture-containing raw foods with hot oil produces grease splattering. Most times, the splattering liquids and food particles reach out of frying apparatuses to considerable distances. These will not only mess up stovetops and surrounding surfaces but also create undue oil burn injuries to the people who are preparing fried foods. The problem of grease fires in the kitchen as well as severe oil burns to people has been well documented.
Second, oil vapor is produced when oil is heated. The people who are preparing fried foods involuntarily inhale considerable amount of cooking fumes during the cooking process. Oil vapor is harmful to human health and might pose long-term health threats to the people who expose themselves to oil vapor on a very regular base.
Third, the oil vapor generated in the cooking process might easily reach much farther in the kitchen or even other rooms and deposit on the furniture, paintings, electrical appliances, etc., causing long-term hazards to home environment.
Fourth, on the other hand, there is an ever-increasing concern over the amount of oil or fat in one's diet for general public. In particular, a low fat diet is desirable in light of related health concerns. Generally, fried foods prepared using conventional methods and cooking wares contain more fat than other foods.
Many products of deep-frying apparatuses or food processing apparatuses are on the market, including the electric frying apparatus taught by U.S. Pat. No. 6,365,878, issued to Lau, on Apr. 2, 2002. These products are equipped with vertically moving baskets and generally require the food to be immersed deep in the frying oil; which means that large quantity of oil is required. The high quantity of oil needed for proper cooking also means high operating cost due to high energy consumption and longer time for cooking. The quantity of oil absorption by the food is prohibitively high, as well.
The disposal of used oil is going to be an environmental issue. Food processing businesses and restaurants might be able to afford expensive equipment for the disposal or treatment of used oil. But general public will find it difficult in dealing with large quantity of used oil.
Another issue is that the user has to repeatedly stir or turn the food around to separate the food pieces during frying, such that the food can be cooked more uniformly.
Over years, various devices have been developed to address these problems associated with frying at home.
U.S. patent application Ser. No. 10/249,240, filed by myself, on Mar. 25, 2003, teaches a forced venting fry utensil. The fry utensil comprises a container for holding foods and oil, a lid covering on top of the container, a blowing device for forcing fresh air into the fry utensil for facilitating the evaporation of food moisture, and a venting device for filtering and deodorizing cooking fumes.
The aforementioned prior art is concentrating on the issue of splattering of hot grease and food particles and cooking fume treatment. However, It fails to address the necessity of automating frying processes. Without frying process automation, especially at home, consumers have to stir the food or turn the food over in the middle of frying processes. In this case, the generation of hot oil splattering and the escape of oil vapor into the room are still inevitable.
Some patents have been granted in the area of automatic frying apparatuses.
U.S. Pat. No. 5,027,697, issued to De Longhi, on Jul. 2, 1991, teaches a rotating oblique basket fryer for cyclic immersion cooking; which facilitates the elimination of moisture in the food, accelerates the heat exchange process, and favors uniform operating temperatures.
U.S. Pat. No. 5,543,166, issued to Masel, et al., on Aug. 6, 1996, describes a cooking appliance including a drum for receiving the food articles to be cooked. The appliance is characterized in that the finished food is spun about a central axis to spin out unwanted excess of oil.
U.S. Pat. No. 5,611,265, issued to Ronci et al., on Mar. 18, 1997, describes a combination of fryer and charbroiler food cooking apparatus. The excessive oil is separated from the fried foods using centrifugal means.
U.S. Pat. No. 6,453,801, issued to Masel, et al., on Sep. 24, 2002, teaches a cooking appliance and method for cooking food articles by means of a rotary drum. The appliance is characterized in that a liquid container is selectively movable to a raised or lowered position to adjust the oil level with respect to the food articles.
The aforementioned prior arts are concentrating on automatic frying apparatuses with special emphasis on low fat frying. The low fat characteristic is mostly achieved by mechanical means, e.g., centrifugal means. This makes the prior art apparatuses less appealing because mechanical separation devices generally require a large size of the frying apparatus. The manufacturing cost is higher and consequently the higher prices the general public pays to buy these apparatuses. Another reason why these prior art apparatuses do not prevail lies on the fact that the mechanisms for achieving targeted objectives are, to some extent, too complicated, which, again, drives up the manufacturing cost. The effort spent on cleaning these apparatuses after use is another important factor. In addition, they fail to address the issue of cooking fume hazards and moisture removal from inside the frying apparatus.
Low fat frying can be, alternatively, achieved by means of how the food is processed. The key point is that the moisture content residing in the raw food, especially in the surfaces of food pieces, has to be removed as quickly as possible. The removal of the surface moisture content greatly favors less fat absorption, less time for frying, less energy consumption, and foods of great looking, taste, and texture.
U.S. patent application Ser. No. 10/249,399, filed by myself, on Apr. 5, 2003, teaches an automatic frying apparatus having a perforated rotary drum for holding and frying foods removably installed inside a container, and a forced venting system for forcing fresh air into the frying apparatus for facilitating food moisture evaporation and cooking fume treatment. The frying apparatus overcomes all the shortcomings of prior art products.
However, all the prior arts, including the one proposed by myself in U.S. patent application Ser. No. 10/249,399, have a very important drawback; they are specifically addressing the issues associated with deep-frying. These prior art products cannot be used for shallow frying, in another word, stir-frying, which is a widely used food preparing/processing method, especially in oriental cuisine. Shallow frying requires constant stirring. Therefore, grease splattering and oil vapor hazards are among the most important issues to deal with. On the other hand, shallow frying requires much more human effort, whereby automation is highly desired.
Therefore, it remains desirable to provide frying apparatuses that can be used for both deep and shallow frying, that are automatic to minimize the human involvement or chore during the frying process, that favors homogeneous heating of foods, that require minimal quantity of oil for frying foods, that can effectively and efficiently evaporate the surface moisture content of food pieces to achieve the characteristic of low fat absorption and great looking, taste, and texture of foods, that are inexpensive to manufacture and simple and easy to use, and also that are environment, people, and home friendly.